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CY28349B 参数 Datasheet PDF下载

CY28349B图片预览
型号: CY28349B
PDF下载: 下载PDF文件 查看货源
内容描述: FTG的Intel㈢ Pentium㈢ 4的CPU和芯片组 [FTG for Intel㈢ Pentium㈢ 4 CPU and Chipsets]
分类和应用:
文件页数/大小: 20 页 / 222 K
品牌: SPECTRALINEAR [ SPECTRALINEAR INC ]
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CY28349B  
Table 5. Register Summary (continued)  
Name  
Description  
WD_TO_STATUS  
WD_TIMER[4:0]  
Watchdog Timer Time-out Status bit  
0 = No time-out occurs (READ); Ignore (WRITE)  
1 = Time-out occurred (READ); Clear WD_TO_STATUS (WRITE).  
These bits store the time-out value of the Watchdog timer. The scale of the timer is determine by the  
pre-scaler.  
The timer can support a value of 150 ms to 4.8 sec when the prescaler is set to 150 ms. If the prescaler  
is set to 2.5 sec, it can support a value from 2.5 sec to 80 sec.  
When the Watchdog timer reaches “0”, it will set the WD_TO_STATUS bit.  
WD_PRE_SCALER  
RST_EN_WD  
0 = 150 ms  
1 = 2.5 sec  
This bit will enable the generation of a Reset pulse when a Watchdog timer time-out occurs.  
0 = Disabled  
1 = Enabled  
RST_EN_FC  
This bit will enable the generation of a Reset pulse after a frequency change occurs.  
0 = Disabled  
1 = Enabled  
Program the CPU Output Frequency  
“G” stands for the PLL Gear Constant, which is determined by  
the programmed value of FS[4:0] or SEL[4:0]. The value is  
listed in Table 4.  
When the programmable output frequency feature is enabled  
(Pro_Freq_EN bit is set), the CPU output frequency is deter-  
mined by the following equation:  
The ratio of (N+3) and (M+3) need to be greater than “1”  
[(N+3)/(M+3) > 1].  
Fcpu = G * (N+3)/(M+3).  
The following table lists set of N and M values for different  
frequency output ranges.This example use a fixed value for  
the M-Value Register and select the CPU output frequency by  
changing the value of the N-Value Register.  
“N” and “M” are the values programmed in Programmable  
Frequency Select N-Value Register and M-Value Register,  
respectively.  
Table 6. Examples of N and M Value for Different CPU Frequency Range  
Fixed Value for  
Range of N-Value Register  
for Different CPU Frequency  
Frequency Ranges  
50 MHz–129 MHz  
130 MHz–248 MHz  
Gear Constants  
M-Value Register  
48.00741  
93  
45  
97–255  
48.00741  
127–245  
Rev 1.0,November 20, 2006  
Page 14 of 20  
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